Bending Purflng

[scamp]

I want to bend wood purfling that is .08 inches ( black, blue, black....20/20/20 ) on my FOX bending machine. It seems like it makes sense to attach the purflings to a thin piece of "scrap" wood with tape to hold the purfling strips properly in the machine. Does this make sense and if so is there a recommendation on a source for cheap scrap wood that bends easily and is readily available that I can use for this ?

Thanks

[MaineGeezer]

How tall is the purfling? If it's less than the 0.060" thickness, it is going to want roll over and bend the other way. I seriously doubt that tape would hold it.
If it's 0.125" or something like that, you shouldn't have a problem.

[Stray Feathers]

Is this purfling to go between the binding and the side? If so, it is easiest to glue it to the binding first and bend the two as one piece. I use Titebond 3 because of the heat and moisture in the bender. If it is to go between the binding and the top, say, I have bent them without a problem by stacking two together (together they are close enough to the same thickness as the binding) and fastening the stacked pair to a piece of binding to be bent, with wraps of plain white paper, held tight with cello tape. I posted this photo previously, but this one is cropped more. The bindings have BWB purflings glued to them already, and the loose BWB purflings are stacked and wrapped tightly beside the bindings. I think I had to point out before, the binding bundles go in the bender beside the side, not on top as in the photo. Bruce W.

[scamp]

The purfling I am talking about is the purfling between the binding and the top. As suggested, my plan is to glue the purfling that will be on the sides of the guitar to the edge of the binding and then bend both together. Just finished a gluing jig to help accomplish this.

I haven't yet decided on the height of the purfling for the top but if I stack and tape them to the bindings as suggested it seems like they won't roll over.

Also, it seems like a good suggestion to tape the bindings to the purfling and bend them side by side with the sides of the guitar. This way you avoid throw away scrap wood side material used to hold the bindings and purfling material during bending.

Thanks

[Kevin Sjostrand]

That is the way to do side purflings. I suggest you use CA to glue the edge purfling to your bindings. You have alot less chance of them separating when bending.

What I do is use clothes pins to lightly clamp the purfling to the edge of the binding and then wick in the CA between the pins. Remove the pins when dry and wick in the rest...no more clamping needed. Turn them over and wick the full length on the other side. Scrape them flush with a razor blade or scraper. These won't come apart from the heat and moisture when bending.

If have 4 strips to bend, tape them together side by side in about 4 or 5 places. Lay them purfling to purfling. You want to be sure you'll have two top and two bottoms right?

Then you can bend them in your bender without the sides.
Lightly mist and wrap in craft paper and foil if you like .
If the foil is wrinkled and not smooth on the wood surface it can transfer to the wood so leave off the foil if you don't think it's necessary.

Typically your edge purfling is .060" or less like standard BWB, so if you just use 1/4" tall binding cut the channels a few thousands deeper. Leave enough height so you can scrape a little off flush with the top when done. Do what looks good to you for finished height.

I personally like a thinner edge purfling like a BW or WB at .020 or .040". Or just a thin black.

[scamp]

Kevin

I was also worried about what heat would do to the bindings with an attached purfling.
I saw on the web that there were quite a few "experts" doing this with Titebond original glue but it seems like that's asking for trouble.
In my search for just the right veneer for this next guitar I had the opportunity to correspond with Jeff Jewett ( from Jeff Jewett guitars...... if you haven't seen his guitars take a look.. very nice).
He told me to use Clear Non-Foaming Gorrilla Glue ( which is what he uses ).

So... I put together a gluing jig to test it out. It is basically three long pieces of 1/2 inch plywood cut so when clamped to a 3/4 inch plywood base they act like a wedge and force the binding and purfling together . See below.

IMG_0527.JPEG

I had some scrap walnut and mahogany so I made some walnut bindings and mahogany purfling so I could practice gluing this way ( not a great combo but what i had). Seems to work well using the clear Gorrilla glue. Given your input I may use same jig to try CA glue method. I think CA glue falls apart above 350 degrees F so it's probably good as well.

IMG_0528.JPEG

IMG_0532.JPEG

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[Kevin Sjostrand]

I've used a similar jig to do the job when I used Titebond 3 which worked but I did experience some delaminating. Nit the process but the glue I presume.

If that Gorilla glue works then I'd say go for it.
One reason I like the CA wicking is you can make sure the strips are positioned correctly while clamping and you're not fighting time with the glue process and trying to keep parts lined up.

I've also switched to gluing on wood bindings using CA for the same reason. Tape in place making sure the fit is great then apply the glue.

Anyway you'll get it working the best way for you.
Test the Gorilla glue up by bending some and see how it comes out. If it works for Jeff it should work for you.

Glad to see you keeping up the building. It gets in the blood doest it?

[scamp]

I think I’ll try some experiments with CA glue. Sounds like it might be a good alternative. One thing I was wondering about. There is a concern about CA glue staining spruce so hence the recommendation to seal the spruce tops before using the glue to attach binding, purfling etc. Is there any issue/concern about the CA glue staining the binding/purfling wood? Are there any woods for the binding/purfling that should be avoided or sealed before gluing?

[bftobin]

I've heard a lot of guys use TB 3 for that.

[scamp]

Thought I would give an update on my purfling/binding glue experiment as others may find the info useful.
I made four bindings out of scrap walnut and for purflings to glue onto these bindings out of scrap mahogany.
I glued up two of the binding/purfling pairs using clear non-foam Gorilla glue using the jig I built (see photo already posted) that forces the binding/purfling together.
I also glued up two of the bindng/purfling pairs using CA glue. I used the same jig to force the two together and wicked the CA glue into the seam and then used an CA accelerator.
After this i scraped them down using a single edge blade and then did a bit of sanding to clean them up as best I could.
Below is a picture of the two pairs.... CA on the right and Gorilla Glue on the left.
What was surprising was the seam between the walnut and mahogany using the Gorilla glue was almost perfect.
The CA glue, however, seemed to darken the wood and fill in the grain a bit and it was much harder to scrap and sand. Additionally, the seam between the walnut and mahogany was much more apparent with the CA glue ( you probably need to zoom in on the picture below to really see this).

IMG_0536.JPEG

I then bent the bindings with purfling attached using my Fox bender to an OM shape. Went up to 350 degrees F and then back down to 250 for about 15 minutes. Both the Gorilla glue and CA glue held up well with no delamination.

Anyway.. that was my experience. I think I will use the Gorilla glue. I may have done something wrong with the CA glue but not sure what.

Hope you find this helpful an as always interested in comments/feedback.

Scamp